Who must file
Traders, farmers keeping books and self-employed professionals file a yıllık gelir vergisi beyannamesi even in a year with no profit. Everyone else files only if their income is of a kind the law says must be declared — an employee taxed at source by a single employer normally files nothing. Companies file a kurumlar vergisi beyannamesi instead.
Tax year and deadline
The tax year is the calendar year. The annual income tax return covering the previous year is filed between 1 March and 23:59 on the last day of March. The tax is paid in two equal instalments, end of March and end of July. Corporate returns are due in the fourth month after year end — 1 to 30 April for a calendar-year company — with the tax paid in the same window. Provisional tax has had four quarters since 2025, due on the 17th of May, August, November and February.
Filing step by step
- Close the year first: since Law 7571 you do not apply enflasyon düzeltmesi for 2025, 2026 or 2027, whatever the inflation figures say.
- If you are on basit usul, işletme hesabı or self-employed, your books are already at defterbeyan.gov.tr and the return is generated from them.
- If you have only rental, wage, securities or other non-business income, use Hazır Beyan — GİB has pre-filled it, you check it and send it.
- Otherwise your accountant prepares it in the Beyanname Düzenleme Programı and transmits it through e-Beyanname.
- Pay the first instalment by the end of March; late payment runs at 3,7% a month.
Penalties for filing or paying late
Late or unfiled returns carry two separate consequences under the Tax Procedure Law. Tax lost because the return came late is a tax-loss offence (articles 341 and 344). The penalty is cut by half when the return is filed late but before an inspection or an assessment commission referral begins (article 344, third paragraph), and raised by half where the taxpayer was carrying on business without having registered (added by Law 7524 of 28 July 2024). It rises to three times the tax where the offence involves the false-document acts listed in article 359. A taxpayer who reports their own failure in a written petition before any inspection starts escapes the tax-loss penalty under article 371, provided the missing return is filed or the wrong one corrected within fifteen days and the tax is paid within the same fifteen days with late-payment interest for each month or part month.